The field of the present disclosure relates to methods for producing silane and, particularly, methods which include use of columnar reactors in which a feed gas and hydride feed are introduced. Some particular embodiments are directed to methods which involve reacting a halosilane (e.g., a silicon tetrahalide gas such as SiF4) and a hydride (e.g., an alkali or alkaline earth-metal salt of aluminum hydride such as NaAlH4) to produce silane.
Silane is a versatile compound that has many industrial uses. In the semiconductor industry, silane may be utilized for deposition of an epitaxial silicon layer on semiconductor wafers and for production of polycrystalline silicon. Polycrystalline silicon is a vital raw material used to produce many commercial products including, for example, integrated circuits and photovoltaic (i.e., solar) cells that may be produced by thermal decomposition of silane onto silicon particles in a fluidized bed reactor.
Silane may be produced by reacting silicon tetrafluoride with an alkali or alkaline earth metal aluminum hydride such as sodium aluminum tetrahydride as disclosed in U.S. Pat. Nos. 4,632,816 and 5,075,092, both of which are incorporated herein by reference for all relevant and consistent purposes. This process is characterized by high energy efficiency; however, starting material costs can negatively influence the economics of such a system.
A continuing need therefore exists for economical methods for producing silane and for methods that may relatively improve reactor productivity and conversion of the various reactants.